TypeScript Recipes vs Learn TypeScript | Code & Run

Tap Run and the real output appears right under the code, along with any type errors. You know what the code does before it goes into your project. No Node.js or TypeScript to install, no IDE, no account. 360+ short examples, one task each. Over 90% run on Node.js 24 and pass strict TypeScript 7 type checking. You know what you need, but not the exact syntax: • How do I remove duplicates from an array? • How do I get an enum value from its name? • How do I merge two Maps? Each has a working example here. • 22 sections, including strings and dates, arrays and collections, classes and interfaces, enums, generics, arrow functions, async/await, exception handling, regular expressions, files, JSON, algorithms, and design patterns. • What changed from TypeScript 3.0 to 5.5, with before-and-after code: the unknown type, the ?. and ?? operators, template literal types, the satisfies operator, using declarations. • Reference, 120+ entries: keywords, operators, and utility types such as Partial, Pick, Record, and ReturnType. Tap a word in the code to look it up. • 200+ SQL queries: JOIN, GROUP BY, subqueries, window functions; more than half run on a practice database. • Search looks inside the code: type reduce to find every example that uses it. • Edit an example and run your version, or write your own: a type error shows up right away. • Works on iPhone, iPad, and Mac. • Everything except running code works offline. Free version: 190+ TypeScript examples and 120+ SQL queries, the full reference, and 12 runs and 12 edits a day (TypeScript and SQL runs share one limit). Full version: all examples and queries, unlimited edits and examples of your own, and up to 30 TypeScript and 80 SQL runs a day. One-time purchase, no subscription. Built by a developer for developers. The project behind it has been in active development since 2015.

Learn TypeScript and write JavaScript that scales — types, generics and real project patterns. Bite-sized lessons with a code runner on your phone and an AI mentor that gives you instant, clear answers. Made for JavaScript developers levelling up, and for beginners aiming at frontend or Node.js jobs. WHY LEARN TYPESCRIPT? • TypeScript is the default for serious JavaScript work — React, Angular, Node and most modern codebases expect it • Typed code means fewer runtime bugs and much better tooling: autocomplete that actually knows your code • It's one of the most-requested skills in frontend and full-stack job listings • If you know JavaScript, you're closer than you think — TypeScript builds on what you already know WHAT YOU'LL LEARN • TypeScript fundamentals — types, variables, functions and control flow • The type system in depth — unions, narrowing and discriminated unions • Generics — write flexible code that stays type-safe • Type inference, utility types and everyday patterns • Using TypeScript with React components and Node.js backends • Strict compiler options, tooling and production-ready workflows EVERYTHING YOU NEED TO LEARN TYPESCRIPT • AI Mentor — confused by a generic constraint or a compiler complaint? Ask anything and get a clear answer in seconds • 100+ bite-sized lessons (5–10 minutes each) — short but genuinely deep • Real code editor — write and run code right on your phone • Quizzes and coding challenges after every topic to lock in what you learn • Weekly Code Challenge — compete with learners around the world • Certificate of completion — pass the final exam and prove your skills • Streaks, progress tracking and smart reminders to keep you consistent • Learn on the go — lessons load fast and keep working on flaky connections • App available in 22 languages WHO IT'S FOR • JavaScript developers who keep seeing TypeScript in job posts and codebases • React and Node developers who want end-to-end type safety • Beginners who'd rather learn the modern standard from day one • Anyone prepping for frontend or full-stack interviews MIGRATE WITH CONFIDENCE Already have a JavaScript project? The migration lessons show you how to adopt TypeScript gradually — file by file, without stopping feature work. Part of CoddyKit — a family of 40+ coding apps trusted by 100,000+ learners worldwide. Free to start: your first course is free, with a daily AI Mentor allowance. Pro unlocks every course, removes ads and gives you unlimited AI Mentor. Download now — your future self (and your linter) will thank you. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://www.coddykit.com/terms/privacy-policy Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://www.coddykit.com/terms/privacy-policy Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://www.coddykit.com/terms/privacy-policy